Newark727
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New Lens, New Problem

Sun Oct 28, 2012 7:24 pm

Yesterday I came into the possession of a brand new Canon EF 24-105mm f4L IS USM lens, and I've been trying it out. Right now for airplanes it seems to have mixed performance, getting a few very crisp shots, many unfocused shots, and not a lot in between; also a tendency toward graininess that may just be me underexposing a lot of my pictures. The auto-focus seems a lot more sensitive than my last similar lens (a Canon 28-135) and maybe I'm not as focused as I think I should be sometimes. That's okay right now at least as I haven't quite found a sweet spot for settings with it. However after a total of 177 or so exposures my almost-three-year-old 50D displays "Error Code 30" which apparently refers to a shutter problem. I turned it off, got it again, turned it off and removed the battery and lens before reattaching them, and got it a third time. Now that I'm home though I went through the same song and dance, put on a different lens, and haven't had the problem again, with either the new 24-105 or anything else.

So, I guess I'm wondering now: how worried should I be? And if there is in fact a major problem with the 50D, would it have anything to do with the image quality of the new lens?
 
JakTrax
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RE: New Lens, New Problem

Sun Oct 28, 2012 7:37 pm

Yes, classic example of how some copies of this lens perform. I never had the error message with my 50D (I have heard about such problems with the 24-105 and 50D though, so I wouldn't worry too much) but the inconsistency in image sharpness was an issue for me. My first copy just produced nothing but OOF shots, so it went straight back. The second was a little better - I'd shoot, say, 6 consecutive shots in a burst and 2 would be sharp, while 4 would be blurry. I sent that one back and requiested a third example - the one I have now - which is pretty spot on. The focus still wanders on the odd occasion on AI servo (one-shot AF seems to sort it) but not frequently enough for me to worry. Most wide-angles I've used have this trait; in fact every lens can have a 'spasm' moment where the focusing gets knocked out slightly.

I'd send it back and keep demanding a replacement until you're satisfied. You will eventually get one you'll be really pleased with. I did!

Karl
 
dazbo5
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RE: New Lens, New Problem

Mon Oct 29, 2012 8:32 am

Newark727,

I would agree with Karl, send it back for a replacement. The copy I have is spot on so it sounds like you've been unlucky and got a bad copy.

Darren
Equipment: 2x Canon EOS 50D; Sigma 10-20 EX DC HSM, 50-500 EX APO DG, Canon 24-105 f/4 L, Speedlite 430EX
 
ckw
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RE: New Lens, New Problem

Mon Oct 29, 2012 12:56 pm

I'm always a bit wary of the 'duff copy' issue - sure, they exist, BUT in many cases it can be more a matter of the lens behaving differently to how you're used to. Before sending a lens back, subject it to some controlled tests - real world situations introduce all kinds of additional environmental or personal issues. Remember, if lens quality varies, it is quite possible that you end up exchanging good for bad!

1 - Error 30 is supposed to relate to the shutter, but it can be either a mechanical or electrical (comms) problem, hence it is not impossible that it could be caused by dirty lens/body contacts - worth giving these a clean. If the shutter (or mirror mechanism) is mechanically defective you normally see error 20. Repair time.

2 - If the error 30 is indeed a lens comms issue, then this could also affect AF if the camera can't tell the lens what to do.

3 - Is there any pattern to the OOF images - are they all at the short or long end of the zoom range? If so, then it is likely a physical problem with the lens. Check this by performing a series of exposures at different focal lengths on a well lit contrasty target using a tripod.

4 - were you using IS or not? This is (disappointingly) a single mode IS system. If you are panning with the IS switched on, results can be unpredictable.

5 - The AF on the 24-105 is much faster/sensitive than on the 28-135. This means if you are using multiple focus points, the system can be easily "distracted" - eg. the lens may lock on to the nose, but a flash of sun further down the fuselage can cause the focus point to shift.

Again, 'bad copies' are of course possible, but I do think they are fairly rare (or certainly rarer than some forums would lead you to believe) - myself, I must have owned a couple of dozen Canon lenses in my time, and never had an issue with quality control. Maybe I'm just very lucky  

Cheers.

Colin
Colin K. Work, Pixstel
 
Newark727
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RE: New Lens, New Problem

Mon Oct 29, 2012 1:22 pm

Hmm, lots to think about now, thanks for the replies. ckw: it seems that most of the images I took, out of focus or not, were using 55mm or more, just taking a quick look at them- I don't think there's much more of a pattern than that. I think I was using IS for almost all of them; it was switched off for maybe one of the fifteen or so arrivals I photographed if that. AF being fast and sensitive definitely squares with what I observed, although I was only using one focus point; I tried to change AF modes to get around this but only got so far and it was after that that Error 30 started happening. I kind of want to get the 50D body checked out first, but if I'm doing that at the camera store where I got the lens I might be able to at least ask about general quality control on this lens.
 
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RE: New Lens, New Problem

Mon Oct 29, 2012 1:27 pm

Quoting ckw (Reply 3):
4 - were you using IS or not? This is (disappointingly) a single mode IS system. If you are panning with the IS switched on, results can be unpredictable.


Switch the IS off and try again. I have found on my copy that the (old) IS is really of no use at all when the aircraft are moving and will most probably result in many blurry pictures (I suspect they are actually more blurry than OOF, but a slightly blurry image will be practically indistinguishable from a slightly OOF image).

Cheers,
Andres
Just sit back, relax and have a glass of Merlot...enjoy your life!
 
JakTrax
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RE: New Lens, New Problem

Mon Oct 29, 2012 2:31 pm

I mainly use the centre focus point only. All lenses can get distracted and produce the odd rogue image; my copy is only slightly more susceptible to this than my 700-200 and 100-400.

Like the others though I do recommend you turn off IS when shooting moving aircraft (even if they are only trundling slowly to the runway). Being primarily a landscape/walk-around lens it only has the single, original IS mode, which can only be effectively used on static subjects.

If that doesn't work I would return the lens and try another. I agree with Colin about some returns not actually being faulty but I can assure you my first 24-105 was not right. His theory doesn't ring true for me because the final copy I had was near-perfect - so unless my technique suddenly changed overnight the first two were duff.

It's normally easier I think to determine faults with wider-angle lenses as they are less affected by atmospheric phenomena than their longer-range stable-mates.

Karl
 
ckw
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RE: New Lens, New Problem

Mon Oct 29, 2012 3:32 pm

Quoting JakTrax (Reply 6):
His theory doesn't ring true for me because the final copy I had was near-perfect - so unless my technique suddenly changed overnight the first two were duff.

More an observation than a theory - bad lenses do happen, no question about that ... but not on nearly the scale that some would have you believe. Anyone following Dpreview would begin to wonder if Canon ever produces a good lens - yet remarkably most who complain they got a bad one (based on a couple of shots of their cat after unboxing) manage to receive a perfect example as a replacement. Perhaps Canon make a good and bad example of each lens and just keep the good ones for people who complain  

The other thing to keep in mind are tolerances. Both bodies and lenses are produced to acceptable tolerances (one of the reasons recent cameras include a microfocus adjust). In terms of exposure for example, 1/3rd of a stop either way is within tolerance.

Hence, if you happen to have a body at one end of the tolerance range you may see more lens issues than with a body that's bang on. I think if I had a succession of lenses which appeared defective I would get the body checked as well.

In less "disposable" times (when people kept their kit for many years) it was common practice for serious photographers to send both their lenses and bodies in for servicing to have them matched - of course exposure, colour and the like were much more critical when shooting slide film.


Cheers,

Colin

[Edited 2012-10-29 08:35:20]
Colin K. Work, Pixstel
 
unattendedbag
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RE: New Lens, New Problem

Mon Oct 29, 2012 4:18 pm

Quoting Newark727 (Thread starter):
Yesterday I came into the possession

What does that even mean? Did you buy the lens? If so, I would exchange it or return it. Was it given to you as a gift? I would ask the gift giver if they still have the receipt. Did you find it on the ground? If so, sell it on ebay and use the money to buy a new one.

However, I think a check of the camera is your higher priority.

Quoting Newark727 (Thread starter):
also a tendency toward graininess

I think that may be a problem with the camera.
Slower traffic, keep right
 
JakTrax
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RE: New Lens, New Problem

Mon Oct 29, 2012 5:28 pm

Quoting unattendedbag (Reply 8):
I think that may be a problem with the camera



Without doubt. The only reason you'd notice more grain is if the lens was making the camera expose irregularly. My 24-105 has a habit of making my 50D over-expose if left at the default setting, often by up to 2/3 of a stop. If you're not correctly exposing for whatever reason you may see more grain in the finished edit.

I checked the 'tolerance' of my 50D when I started having problems with the 24-105, but it turned out to be fine. I agree fully with Colin that you can sometimes be unlucky with the tolerances of your camera/lens - but rather than viewing it as something to be corrected by MA (which let's not forget many DSLRs don't have) I look at it as a minor fault with the manufacture. I think the tolerances should have much narrower margins, especially when you think how much you're paying for these so-called professional 'tools'. If I'm paying in excess of GB£1,000 for a lens that claims to go to 400mm, I want and expect it to be usable at that focal length - but within the limits of what atmospheric conditions will allow. Some people get their 100-400s, go out in summer on the equator at mid-day, shoot 747s at 400mm and moan about the quality. You have to be realistic, but to me your lens does sound like a bad copy.

Karl
 
Newark727
Topic Author
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RE: New Lens, New Problem

Mon Oct 29, 2012 6:00 pm

Quoting unattendedbag (Reply 8):

What does that even mean? Did you buy the lens? If so, I would exchange it or return it. Was it given to you as a gift? I would ask the gift giver if they still have the receipt. Did you find it on the ground? If so, sell it on ebay and use the money to buy a new one.

However, I think a check of the camera is your higher priority.

It was a gift, that I was involved in selecting. So yeah, receipt is still around. I'll check it without IS more comprehensively when I next get a chance, which probably won't be today, then I'll see what's up at the store it came from.
 
ckw
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RE: New Lens, New Problem

Mon Oct 29, 2012 10:34 pm

Quoting JakTrax (Reply 9):
I think the tolerances should have much narrower margins, especially when you think how much you're paying for these so-called professional 'tools'.

Yes, but pefection costs a lot more - that last few percent sends the price skyward. Just look what a Leica goes for (and even they have problems from time to time)! Remember, pricey though Canon gear is, it's still mass produced goods. For perfection you're looking at hand crafted. Of course this is a very good reason for buying from a reputable dealer - makes exchanges and/or adjustments much more hassle free. A good relationship can really pay off in the long term

Cheers,

Colin
Colin K. Work, Pixstel
 
Tonyholt777
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RE: New Lens, New Problem

Fri Nov 02, 2012 10:06 am

Some very good points covered here, Colins 1 to 5 nicely sum it up.

FWIW I use my 24-105mm L with my 5D mkii on weddings and commercial work and its a good combo. However, you do have to watch the settings. It gives very sharp results from the centre out to the edges especially when stopped down f5.6 - 11 dependent on what your shooting.

Agree the IS is best not relied upon being pretty old hat although it can and does get the odd shot sometimes. I use manual for most of my stuff and with the 24-105 I tend to use 1/125 s as default on the shutter which mainly gives me the result, this lens goes from fairly wide to short tele quickly.

Can't comment on the 50D, never had one, thats more Karls area.

good luck

tony

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